ROOT!T's electronic temperature controller is compatible with all heat mats and is an optional accessory for the ROOT!T Heat Mats. The thermostat turns the heat mat on and off. To maintain optimum temperatures, use ROOT!T Heat Mats with the ROOT!T Thermostat giving ultimate temperature control during propagation. It has an easy plug-in operation and is easy-to-use and control. The temperature control range is 20°C to 42°C .